Spring cushion structures

ABSTRACT

An adhesive plastic net is used over a spring foundation both as a spring insulator and as a spring positioner, being adhered to the springs by the adhesive material of the net itself.

United States Patent Ronald L. Larsen Minneapolis, Minn. 769,210

Oct. 21, 1968 Apr. 27, 1971 Conwed Corporation St. Paul, Minn.

Inventor Appl. No. Filed Patented Assignee SPRING CUSHION STRUCTURES 4 Claims, 3 Drawing Figs.

US. Cl

Int. Cl

Field of Search [56] References Cited UN1T ED STATES PATENTS 3,184,767 5/1965 Meyers 5/354X 3,273,179 9/1966 Ridenour 5/354 3,315,283 4/1967 Larsen 5/354 Primary Examiner-Casmir A Nunberg Attorney-Gunnar A. Gustafson, Jr.

ABSTRACT: An adhesive plastic net is used over a spring foundation both as a spring insulator and as a spring positioner, being adhered to the springs by the adhesive material of the net itself.

PATENTEUAPRZYIQYI 3,576,040

INVENTOR 'RQMALI) LA LARSEM SPRING CUSMON STRUCTURES It is known to provide various nets of natural or synthetic fibers or of extruded plastic to serve as a spring insulator in cushion structures such as loose cushions, furniture decks, mattresses, and the like.

It is also known to adhere such spring insulators to the underlying spring structures of coil springs or sinuous springs in order to avoid dimpling" and in order to eliminate the wire ties commonly associated with such structures.

When such net is used as a spring insulator and is adhered to the underlying springs, it is necessary to perform separate operations to apply the adhesive and to use additional adhesive material. 7

One object of this invention is to provide a plastic net spring insulator of adhesive material thus eliminating the added adhesive needed and the added application of adhesive.

Another object of this invention is to replace two materials (a spring insulator and an adhesive) with a single-adhesive net structure.

These and other objects of the invention will be apparent to those skilled in the art from the following specification and drawings in which:

FIG. 1 is a view of a portion of the net of this invention,

FIG. 2 is a cross-sectional view of a portion of a spring structure, and

FIG. 3 is an enlarged view taken along the lines 3-3 of FIG. 2.

In my U.S. Pat. No. 3,315,283, a plastic net spring insulator is disclosed which may be adhered to a felted-fibrous, matcushioning material. This combination product is then placed over the face of a spring foundation to provide a combination spring insulator and cushioning mat for a cushion structure such as loose cushions, upholstered furniture, mattresses, furniture decks, and the like. As further described in said U.S. Pat. No. 3,315,283, the plastic net spring insulator, either alone or in combination with an adhered felted fibrouscushioning mat is hog ringed to the periphery of a spring foundation. Said patent also refers to the possibility of adhering such spring insulator to the spring foundation in accordance with the teachings of U.S. Pat. No. 3,070,814. In said U.S. Pat. No. 3,070,814, a bonded structure is disclosed in which a spring insulator net is adhered to the spring foundation by added adhesive whereby the normal ties and wires between springs may be eliminated, thus permitting variety in the location of springs with the springs being held in place by the net insulator itself.

One way of adhering such spring insulator nets to the underlying spring foundation is by dipping the spring coils in a hot-melt material which can then be heat-activated by an induction heating mechanism or other heating means when in place against the net. This causes the net to be adhered to the spring foundation. Another known method of adhering the net spring insulator to the spring foundation is to apply strips of hot-melt adhesive to the combination cushioning materialspring insulator net in long strips and then in a continuous manner applying such combination to the spring foundation. The metal wires of the spring foundation are heated by an electrical heat induction mechanism and the hot wires of the spring foundation cause the strips of adhesive to flow sufiiciently to secure the cushioning material and the spring insulator net to the spring foundation. This latter method of application, of course, is applicable only when the net has a cushioning mat secured thereto which carries the strips of hotmelt adhesive. It is not applicable when the net is applied alone to the spring foundation. Such construction results in an excessive use of adhesive material since much of the adhesive material in the wide spaces between the wires of the springs is not utilized.

Applicant has discovered that by the use of a plastic spring insulator net formed from a suitable hot-melt adhesive, both the adhesion function of the spring insulator to the spring foundation and the spring insulator function may be accomplished with a single unitary structure.

As shown in FIG. 1 the adhesive plastic net 10 of the invention comprises a plurality of longitudinal strands I2 and a plurality of transverse strands 14. In the preferred form the net 10 has larger strands l2 and relatively smaller strands 14 with the strands 12 being lesser in number than the strands 14. For example, the preferred form has about one strand 12 for each three-fourths inch whereas there are about four strands 14 per inch. Such nets are preferably produced by extrusion in accordance with the methods and apparatuses disclosed in U.S. Pat. No. 3,252,181, or as disclosed in U.S. Pat. Nos. 2,919,467 and 3,051,987. Such plastic nets may be extruded with any predetermined number of strands in either direction and with varying sizes of strands. As shown in FIG. ll, strand 12 is preferably considerably larger in diameter than is strand 14. Additionally, it will be seen that the strands l2 and the strands 14 are relatively planar on one side, (the side toward the viewer in FIG. 1) and that the strands 12 project upwardly higher than the strands 14 on the other side. This is better shown in FIGS. 2 and 3.

The flexible plastic adhesive net 10 may be formed from any one of a number of extrudable plastic materials which are suitably adhesive to metal and notably to spring metal when heated as, for example, by being brought into contact with hot springs. Such materials include various plastic resins including certain polyesters, and in particular, certain ionomers such as Surlyn-A as manufactured by E. I. du Pont de Nemours & Co., Inc. Such material is readily extrudable and when heated by contact with the hot wire spring foundation will flow to cause it to adhere to the wire of the springs.

FIG. 2 shows a portion of a completed construction of a cushion or furniture deck incorporating coil springs 16 although sinuous S-springs could equally well be used. In constructing the deck or cushion the wires 18 of the top convolutions of the coils 16 in combination present a substantially flat or slightly curved face to which the spring insulator net is to be applied. The springs 16 are held in selected arrangement by any suitable holding mechanism and are then heated by any suitable means such as an electric induction heater. The plastic adhesive net insulator 10 is then laid over the face of the foundation. The heat of the wire springs causes the adhesive material of the net 10 to flow somewhat and adhere as shown at 20 to the spring wire 18 of the springs 16. The adhesive material 20, of course, flows from the net 10 primarily from the strands 12, although if sufficient heat and pressure is used, some of the material may flow from the smaller strands 14. It is preferred that the strands 14 not be disturbed by the heat induction step of the application method.

The cushioning material 22 shown as a felted fibrous mat such as that sold under the trademark TUFFLEX by Conwed Corporation of St. Paul, Minn., may then be applied over the spring insulator l0 and additional filler or cushioning materials, finishing upholstery, and the like may then be applied to the top surface of the cushioning material 22. The specific desired construction of the cushion, mattress, or deck will determine the particular materials used on top of the spring insulator 10. In some applications the mat 22 may not be used and in others it may be secured to the plastic adhesive net 10 before the net 10 is applied to the spring foundation.

While only a few points 20 where the material of the large strand 12 has flowed to adhere to the wire 18 of the coils 16 are shown, it will be obvious that at each point where the wire 18 of the top convolution of the coils 16 crosses a strand 12 (or even a strand 14) of the net 10 there will be flow of the resin as at 20 and adhesion to the wire 18.

it will be seen from the foregoing that the advantages of an adhered spring insulator such as disclosed in U.S. Pat. No. 3,070,814 are obtained without the use of additional applied adhesive and the necessity of having complicated, dirty, and expensive equipment to apply such adhesive. Accordingly, the plastic adhesive net 10 of this invention is more convenient to use and replaces two prior materials, i.e., the spring insulator net and the requisite adhesive, with a single unitary plastic adhesive net structure. in order to distinguish the adhesion of the net of this invention to the wires 18 by means of the plastic adhesive of the net itself from prior structures where applied added adhesive was required, the adhesion with the material of the net itself as described herein is referred to as self-bonded.

While, as described herein, induction heating has been referred to, it will be obvious that other heating means may be employed such as hot rolls, localized flame applicationsoven heating, and others.

It will also be obvious from the drawings that while some of the plastic adhesive material of the net 10 flows to adhere the net 10 to the spring wires 18, most of the material remains in place to serve as the spring insulator net. The specific design of the net with respect to numbers of strands in either direction and sizes of strands in either direction as well as the total overall thickness of the net can, of course, be selected for any specific application; for example, some differences in strand count and diameters may be required for different coil counts in a mattress.

While plastic adhesive net of the extruded variety as produced by the methods and apparatuses disclosed in U.S. Pat. Nos. 3,252,181 and 3,349,434 are preferred because of the right angular arrangement of the sets of strands (with accompanying rectangular openings) and the integral joints provided by such methods and apparatuses (as illustrated by the net 10 of H68. 1, 2, and 3), plastic adhesive net produced by other extrusion methods and apparatuses such as those disclosed in U.S. Pat. Nos. 2,919,467 and 3,051,987 may also be used. The latter methods and apparatuses also provide a net with an integral joint but the sets of strands of the net are at other than right angles and thus have diamond, hexagonal or other shaped openings. in certain constructions it is also possible to use adhesive plastic nets of woven rather than the extruded variety, although the extruded right angular nets are generally to be preferred.

I claim:

1. A spring structure comprising a resilient metal wire spring foundation presenting a face having relatively large open spaces between a multiplicity of relatively small wires in said face, an open mesh plastic spring insulator net over said face, said net having a plurality of sets of flexible strands, each of said sets having the strands thereof substantially parallel, one of said sets of strands being arranged at an angle to a second set of said strands, at least a portion of said net being an adhesive, said net being secured to the wires of said foundation at points of contact therewith by the adhesive material of said net whereby said net is self-bonded to said foundation and serves as a spring insulator for said foundation.

2. The spring structure of claim 1 in which said net is an extruded net, the material of said net is an extrudable plastic adhesive, and the points where the strands of said one set meet the strands of said second set form integral joints.

3. The spring structure of claim 1 in which said net is a woven net.

4. The spring structure of claim 2 in which the angle between the strands of said one set and the strands of said second set is substantially a right angle. 

1. A spring structure comprising a resilient metal wire spring foundation presenting a face having relatively large open spaces between a multiplicity of relatively small wires in said face, an open mesh plastic spring insulator net over said face, said net having a plurality of sets of flexible strands, each of said sets having the strands thereof substantially parallel, one of said sets of strands being arranged at an angle to a second set of said strands, at least a portion of said net being an adhesive, said net being secured to the wires of said foundation at points of contact therewith by the adhesive material of said net whereby said net is self-bonded to said foundation and serves as a spring insulator for said foundation.
 2. The spring structure of claim 1 in which said net is an extruded neT, the material of said net is an extrudable plastic adhesive, and the points where the strands of said one set meet the strands of said second set form integral joints.
 3. The spring structure of claim 1 in which said net is a woven net.
 4. The spring structure of claim 2 in which the angle between the strands of said one set and the strands of said second set is substantially a right angle. 